Spring Securiy OAuth2 跨域问题解决笔记

在学习Spring Security OAuth2时，使用前后端分离，前端端口8080通过ajax访问端口为8083的后端，发现一直报错cors block…
之后在查询各大解决方案时有说用

.permitAll()
    .antMatchers(HttpMethod.OPTIONS)
    .permitAll()
.requestMatchers(CorsUtils::isPreFlightRequest)
    .permitAll()

或者，在返回corsFilter的方法上添加@Bean都没有成功
最后通过实现 Filter接口自己写一个cors的过滤器成功了

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CorsConfig implements Filter {

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        //允许所有的域访问
        response.setHeader("Access-Control-Allow-Origin", "*");
        //允许所有方式的请求
        response.setHeader("Access-Control-Allow-Methods", "*");
        //头信息缓存有效时长（如果不设 Chromium 同时规定了一个默认值 5 秒），没有缓存将已OPTIONS进行预请求
        response.setHeader("Access-Control-Max-Age", "3600");
        //允许的头信息
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with, authorization");

        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
            response.setStatus(HttpServletResponse.SC_OK);	
        } else {
            chain.doFilter(req, res);
        }
    }
}